Lots of people both extroverts and introverts dislike public speaking because the entire audience is focused on you and seemingly critical of any flaw or mistake you make when most of the time the audience just wants you to finish so they can get on with their life.

Personal tips weblog Dumb Little Man offers insight into this issue:

Someone I respect a great deal once told me that ‘shyness is pride.' What he meant was that shy people spend too much time worrying about themselves and how they look in the eyes of other people, when they should be focusing on what's outside, trying to do a good job, trying to add value to the situation. This is brilliant advice – start thinking about others and less about yourself. In fact, everyone else is actually thinking about themselves, too. Nobody really cares about you. So stop being so self absorbed.

I know the times I've been stuck hearing presenters at awards shows and conferences I politely listen, but don't really care if they're a perfect speaker or just a good one. Stop worrying so much about what your audience is thinking and finish the presentation already. Photo by Cornell University